Field of the Invention
Embodiments of the invention generally relate to expandable tubing assemblies and expanding such assemblies to seal a surrounding annulus.
Description of the Related Art
Drilling a bore into the earth enables access to hydrocarbons in subsurface formations. The process of drilling a borehole and of subsequently completing the borehole in order to form a wellbore requires the use of various tubular strings. Methods and apparatus utilized in the oil and gas industry enable placing tubular strings in a borehole and then expanding the circumference of the strings in order increase a fluid path through the tubing and in some cases to line the walls of the borehole. Some of the advantages of expanding tubing in a borehole include relative ease and lower expense of handling smaller diameter tubing and ability to mitigate or eliminate formation of a restriction caused by the tubing.
Many applications require creating a seal around one of the tubular strings in the wellbore such that fluid flow through a surrounding annulus is blocked. Various types of conventional packers exist that may be set for this purpose without expanding an inside diameter of the tubing. Further, expandable tubing may include a band of elastomeric material disposed on its outer surface to facilitate sealing. However, these bands produce sealing that is localized only at the band and often unreliable due to spring back effect resulting in low seal pressure being achieved.
Therefore, there exists a need for apparatus and methods to improve sealing around tubing that has been expanded.